Nine 6-month-old healthy Qianbei black pigs were randomly divided into 3 groups. The longissimus dorsi muscle(LDM) and psoas major muscle(PMM) were collected. The expression profiles of circRNAs were constructed by RNA-seq, and the differentially expressed circRNAs in LDM vs. PMM were screened. A total of 63 differentially expressed circRNAs were identified in the two muscles of Qianbei black pigs, of which 31 were up-regulated and 32 were down-regulated in LDM. GO enrichment and KEGG analysis were performed on the source genes of differentially expressed circRNAs. The results showed that the source genes of differentially expressed circRNAs were mainly concentrated in GO items such as the regulation of phosphatase activity, sarcomere activity, and positive regulation of myosin-light-chain-phosphatase activity. In the enriched KEGG pathway, the pathways involving muscle fiber type conversion include the regulation of actin cytoskeleton, ECM-receptor interaction, PI3K-Akt signaling pathway. Finally, target miRNAs of differentially expressed circRNAs were predicted, and corresponding target mRNAs of miRNAs were screened to construct the circRNA-miRNA-mRNA regulatory network. The results showed that circ_0003749-miR- 27a-MSTN, circ_0003749-miR-27a-PPARγ, circ_0012316-miR-23a-Myh1/2/4, circ_0007093-miR-214-3p-MEF2C, circ_0010118-miR-132-FoxO1 and circ_0010118-miR-374a-5p-FoxO1 may regulate muscle fiber type conversion through ceRNA network.